1. Field of the Invention
The present invention relates to a turbo compressor and refrigerator.
Priority is claimed on Japanese Patent Application No. 2008-27073, filed Feb. 6, 2008, the content of which is incorporated herein by reference.
2. Description of Related Art
There is known a variable diffuser that changes the cross-section area of a diffuser flow path in a turbo compressor. For example, Japanese Patent Application First Publication No. 2007-211716 A discloses a mechanism that supports at three points an annular member (diffuser ring) that is arranged in a diffuser flow path and transmits in a peripheral direction via a transmission means a driving force for carrying out adjusting the position of the annular member.
In a variable diffuser equipped with an annular member, a force in the axial direction resulting from the pressure difference between the front surface (the surface on the inner side in the radial direction) of the annular member and the rear surface (the surface on the outer side in the radial direction) and the like acts on an annular member.
In the above Patent Document 1 that has a wire-shaped member that is tensioned over the whole in the peripheral direction as a transmission means of the driving force, a portion of the force that acts on the annular member reaches the wire-shaped member, and so the orientation of members in the transmission means or the position adjustment means may become unstable.
Also, in the transmission means that has a circumferential linkage, adjustment of the tensile state of one section affects both neighboring sections thereof. This means there is the possibility of the influence of adjustment of a section affecting all sections. Adjustment of this kind of transmission means is complicated.
A purpose of an aspect of the present invention is to provide a turbo compressor that is capable of changing in a stable manner the position of an annular member that is disposed in a diffuser flow path.